Modeling

Once calibration is done, we are ready to create a 3D model using the
background photo image as a reference. We use a 3D cursor to create the
model.

The 3D cursor is supposed to lie in the world 3D space, and appears
on the screen superposed on the background image. Each of the four sides
can be dragged parallelly within underlying plane. Also it can be rotated
any amound of angle around one of its sides.

The following figures are screen shots from the modeling process in
Photo3D using a photograph of a building.

This is the upper half of a building. The red rectangular shape, which
consists of four red lines is the 3D cursor. On the right side, there are
two rectangles already created. They are rendered in translucent grey.

The left side of the 3D cursor is dragged so that it fits to the edge
of the wall. A rectangle is created there as shown in the next figure.

The 3D cursor is rotated around the left side. It is rotated 90 degree
by default.

A side of the 3D cursor is dragged again to the left edge of building.to
create another rectangle...